With Nazanin Zaghari-Ratcliffe facing yet another Christmas trapped as a hostage in Iran, husband Richard has welcomed the strong language in a new report from senior MPs.

The all-party foreign affairs select committee has put together a document saying that the Iranian Revolutionary Guard Corps should be treated as a terrorist organisation

The committee report said the UK government should take explicit issue with Iran's "state hostage taking" in cases like Nazanin's, and that it should take a leading role in challenging the practice.

Richard Ratcliffe, whose wife approaches her 42nd birthday under house arrest in Tehran, said the family is pleased with the report.

"It was pretty clear that the government is not addressing the issue properly, and had some useful suggestions," he said.

READ MORE: Free Nazanin: Kylie Moore-Gilbert's release 'provides hope for Nazanin'

But he noted the issue of state-hostage taking in Iran continues, saying: "Aside from the threats of executions actually turning into reality, there are more people being taken."

The committee report said the Foreign Office should try to encourage Iran to play a "positive, constructive and predictable role" as a regional power and that the UK's strategy should send a clear message: "Iran's destabilising activities are unacceptable because they adversely impact the region and its people, but that, when the time comes, the door is open for diplomacy."

The US has already listed the Iranian Revolutionary Guard Corps as a terrorist organisation and the committee said the its "clear and enduring support for terrorists and non-state actors working to undermine stability in the region" means Foreign Secretary Dominic Raab and Home Secretary Priti Patel should begin the process of proscribing it.

Committee chair Tom Tugendhat said: "The UK Government must call the arbitrary detention of foreign nationals what it is: hostage taking. The charges, trials and convictions of British citizens on Iranian soil are a parody of a justice system. Using young mothers and retirees as bargaining chips and leverage is an unacceptable form of diplomacy."

Nazanin is far from the only British-Iranian held in Iran, with others including Anoosheh Ashoori, a south Londoner, still in the notorious Evin Prison.

The Ratcliffe and Ashoori families held a private vigil drawing attention to their respective cases at the Iranian embassy in earlier in December.